This invention is related to mounting structures for securing a fluid actuator housing on to the bonnet of a valve. More particularly, this invention is related to the mounting of a pneumatic actuator housing on a sleeve around the stem of a gate valve wherein the mounting structure includes a split ring engaged with the sleeve and secured in place by a retainer.
Several devices are known in the prior art for mounting pneumatic actuator cylinders on gate valves, however, each has certain undesirable characteristics. One such structure for mounting a pneumatic actuator includes a sleeve around the valve stem extending from the bonnet whereupon a collar extending from a center portion of the actuator is mounted. The collar and the sleeve are secured by a set screw that extends through the collar and contacts or extends into a portion of the sleeve. While this mounting arrangement does secure the actuator to the valve bonnets, it requires the set screw to be tight in order to adequately secure the actuator, and provides no mounting support should the set screw become loosened or should it otherwise fail. Another mounting arrangement has a sleeve on the bonnet around the stem with a collar on the actuator housing being slidably mounted on the sleeve. A locking ring is mounted in the exterior of the outer end portion of the sleeve and retained within the inner end of portion of the collar. In this structure the actuator must be first placed over the sleeve then the locking ring inserted, next the actuator is raised or moved outward on the sleeve so the innermost portion thereof surrounds the locking ring. A second locking ring must then be engaged in a groove in the sleeve at the exterior end of the collar to retain the actuator in position on the sleeve. This construction has the inherent disadvantage in that once the actuator is installed, only the second described locking ring holds it in position on the sleeve. An additional disadvantage is that because the locking ring and the portion of the sleeve between the actuator and the bonnet are exposed, weather, paint and rust can damage the exterior of the surfaces of these parts making it extremely difficult to disassemble the actuator for service or replacement after it has been in service for a period of time.